Applications, methods and systems for materials processing with visible raman laser

ABSTRACT

Laser additive manufacturing systems and apparatus using laser wavelengths below 800 nm. Raman laser modules having laser pump sources in the blue wavelength range. Matching functional laser beam wavelength with maximum absorption wavelengths of starting materials.

This application: (i) claims under 35 U.S.C. § 119(e)(1), the benefit ofthe filing date of Aug. 27, 2014 of U.S. provisional application Ser.No. 62/042,785; (ii) claims under 35 U.S.C. § 119(e)(1), the benefit ofthe filing date of Jul. 15, 2015 of U.S. provisional application Ser.No. 62/193,047; and, (iii) is a continuation-in-part of PCT applicationserial PCT/US14/035928, which claims under 35 U.S.C. § 119(e)(1), thebenefit of the filing date of Apr. 29, 2013 of US provisionalapplication 61/817,311, the entire disclosures of each of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present inventions relate to lasers that produce laser beams in the300 nm to 700 nm range, including higher power laser beams in thesewavelengths having excellent beam qualities. The present inventionsfurther relate to laser manufacturing processes, systems and devices,and in particular to laser additive manufacturing processes using thenovel laser beams of the novel lasers of the present inventions.

Prior to the present inventions, laser beams in the 300-700 nm range aretypically obtained from a laser source using frequency doubling of anear infrared or infrared laser. To date is it believed that, in generaland in particular for commercially viable systems, the art has beenunable to scale these types of lasers to make higher power lasers, e.g.,laser greater than 500 W (0.5 kW), and in particular 1 kW and greater.Thus, to date it is believed that the art has been unable to scale theselasers to obtain high power lasers having high beam quality, in the300-700 nm wavelength range. This inability to obtain high power lasersin these wavelengths is generally believed in the art to be limited bythe nonlinear crystal's ability to handle the heat load and fluencelevels required at high power levels, among other things. As aconsequence, the highest power, high beam quality laser available byfrequency doubling is presently believed to be limited to about 400Watts (0.4 kW) pulsed. The pulsing is required to manage the heat loadon the crystal. It is believed that commercially viable or useful lasersin the 300-700 nm range having higher powers, e.g., 1 kW and greater,and having high beam quality, e.g., M²˜1, have not been obtained, priorto the present inventions.

Prior to embodiments of the present inventions, it is believed thatthere were generally four types of blue lasers. Blue lasers are thosethat have wavelengths in the range of about 400-505 nm, and typically405-495 nm. These blue lasers are: (i) He:Cd, (ii) Ar-ion, (iii) diodelaser direct and frequency doubled, (iv) solid state parametricoscillator and frequency doubled and (v) fiber lasers doubled andfrequency shifted fiber lasers doubled.

-   -   (i) He:Cd lasers are single mode but limited in power to a few        hundred milli-Watts, e.g., 0.0001 kW. He:Cd lasers are typically        single transverse mode, but due to the low efficiency of these        lasers (<0.025%) it is very difficult to scale these lasers to        high power levels, consequently, they are not suitable for high        power material processing applications.    -   (ii) Ar-ion lasers are very inefficient, and as a consequence        are limited to relatively lower power, less than about 0.005 kW        multi-lines. These lasers, at these low powers, are single        transverse mode with multiple wavelengths operating. Lifetime of        these systems are typically, <5,000 hours which is relatively        short for most industrial applications.    -   (iii) Blue diode lasers have are recently becoming available.        They however are low power, typically less than 0.0025 kW, and        have poor beam quality, e.g., M²>5 in the slow axis and M²˜1 in        the fast axis. The devices today have lifetimes on the order of        20,000 hours and are suitable for many industrial and commercial        laser applications. When scaling these devices up to 200 Watts        or more, the beam quality decreases with each incremental        increase in power. For example at 200 Watts, the M²>50.    -   (iv) Frequency doubled blue laser sources are typically limited        to about 0.50 kW or so output power. The methods for creating        blue light can be either frequency doubling a 800s-900s nm range        light source or using sum-frequency mixing of two different        wavelengths to generate a third. Either technique requires the        use of a non-linear doubling crystal such as Lithium Niobate or        KTP. These crystals are relatively short and as a consequence,        they require high peak power levels to achieve efficient        conversion. When operating in a CW mode, thermal issues as well        as charge migration issues can result in the rapid degradation        of the crystal and consequently, the output power of the laser.    -   (v) Fiber lasers that are frequency shifted and then frequency        doubled into the blue require the use of a non-linear doubling        crystal such as Lithium Niobate or KTP. These crystals are        relatively short and as a consequence, they require high peak        power levels to achieve efficient conversion. When operating in        a CW mode, thermal issues as well as charge migration issues can        result in the rapid degradation of the crystal and consequently,        the output power of the laser.

Prior to the present inventions, blue wavelength laser beams weretypically obtained by parametric oscillators, four wave mixing anddirect doubling. These are all inefficient processes that rely on theuse of a non-linear crystal to achieve the blue wavelength. Thesecrystals are incapable of managing the heat loads that occur when laserpower approaches a few 100 W (0.1 kW) CW, let alone a kW and greaterpowers.

It is believed that these prior types of blue lasers and the laser beamthey provided are inadequate for use in laser additive manufacturingprocesses or systems. These types of prior blue lasers are believed tobe incapable of obtaining the high power laser beams, e.g., bluewavelengths having 0.1 kW and greater power, of embodiments of thepresent inventions. High power frequency doubled laser sources aretypically rapidly pulsed sources, which can achieve high peak powerlevels and consequently high conversion efficiency. These types of priorblue laser also have temporal characteristics for use in most laseradditive manufacturing, and in particular in the formation of articleshave tight tolerances. These types of prior blue laser cannot providethe high power and CW output of embodiments of the present inventions.

Prior to the present inventions, laser beams in the 450 nm or less weretypically obtained by parametric oscillators, four wave mixing, andfrequency tripling of an IR source. These are all inefficient processesthat rely on the use of a non-linear crystal to achieve the short (200nm-450 nm) wavelength. These crystals are incapable of managing the heatloads that occur when laser power approaches a few 100 W (0.1 kW) CW,let alone a kW and greater powers.

Prior to the present inventions, laser beams in the 700 nm-800 nm rangewere typically obtained by pumping a dye laser, parametric oscillators,four wave mixing, and frequency doubling of an IR source. These are allinefficient processes, the dye lasers tend to bleach out in time andhave a limited interaction volume making it difficult to achieve high CWpower levels. The other processes rely on the use of a non-linearcrystal to achieve the 700 nm-800 nm wavelength. These crystals areincapable of managing the heat loads that occur when laser powerapproaches a few 100 W (0.1 kW) CW, let alone a kW and greater powers.

As used herein, unless expressly provided otherwise, the terms “laseradditive manufacturing” (“LAM”), “laser additive manufacturingprocesses”, “additive manufacturing processes” and similar such termsare to be given their broadest possible meanings and would include suchprocesses, applications and systems as 3-D printing, three dimensionalprinting, sintering, welding, and brazing, as well as any other processthat utilizes a laser beam at least during one stage of the making of anarticle (e.g., product, component, and part) being made. These terms arenot limited to or restricted by the size of the article being made, forexample they would encompass articles that are from submicron, e.g.,less than 1 μm, to 1 μm, to 10 μm, to tens of microns, to hundreds ofmicrons, to thousands of microns, to millimeters, to meters tokilometers (e.g., a continuous LAM process making a ribbon or band ofmaterial).

As used herein, unless expressly provided otherwise, the terms “laserbeam spot size” and “spot size” are to be given their broadest possiblemeaning and include: the transverse cross-sectional shape of the laserbeam; the transverse cross sectional area of the laser beam; the shapeof the area of illumination of the laser beam on a target; the area ofillumination of a laser beam on a target; the “maximum intensity spotsize”, which is the cross sectional area of the laser beam in which thelaser beam is at least 1/e² or 0.135 of its peak value; the “50%intensity spot size”, which is the cross sectional area of the laserbeam in which the laser beam is at least 0.00675 of its peak value; andthe cross sectional area of the laser beam in which the laser beam hasfunctional properties.

As used herein, unless expressly provided otherwise, the terms“functional additive manufacturing laser beam”, “functional beam”,“functional laser beam” and similar such terms, mean laser beams havingthe power, wavelength, fluence, irradiance (power per unit area) andcombinations and variations of these properties to form or build thestarting or target materials into an article; by having the laser beameffect these materials, e.g., sinter, braze, anneal, weld, melt, join,tackify, soften, cross-link, bond, react, etc.

As used herein, unless expressly provided otherwise, the term “about” ismeant to encompass a variance or range of ±10%, the experimental orinstrument error associated with obtaining the stated value, andpreferably the larger of these.

As used herein, unless expressly provided otherwise, the terms “optics”,“optical element”, “optical system”, and similar such terms should begiven their broadest meaning and would include: any type of element orsystem that is capable of handling the laser beam (e.g., transmitting,reflecting, etc., without being damaged or quickly destroyed by thebeam's energy); any type of element or system that is capable ofeffecting the laser beam in a predetermined manner (e.g., transmit,focus, de-focus, shape, collimate, steer, scan, etc.); elements orsystems that provides multiplexed beam shapes, such as a cross, an xshape, a rectangle, a hexagon, lines in an array, or a related shapewhere lines, squares, and cylinders are connected or spaced at differentdistances; refractive lenses; diffractive lenses; gratings; transmissivegratings; mirrors; prisms; lenses; collimators; aspheric lenses;spherical lenses; convex lenses, negative meniscus lenses; bi-convexlenses; axicons, gradient refractive lenses; elements with asphericprofiles; elements with achromatic doublets; micro-lenses; micro-arrays;mems steering mirrors such as used in DLP projectors can be used tocreate and steer images on the fly; lithium niobate beam steeringcrystals; high speed galvanometers; combinations of linear motors andhigh speed galvanometers; flying optic head; deformable mirror devices;and combinations and variations of these and other beam handlingdevices.

This Background of the Invention section is intended to introducevarious aspects of the art, which may be associated with embodiments ofthe present inventions. Thus the forgoing discussion in this sectionprovides a framework for better understanding the present inventions,and is not to be viewed as an admission of prior art.

SUMMARY

There has been a long-standing and unfulfilled need for, among otherthings, lasers to provide laser beams in the 300 nm-800 nm wavelengths,and in particular blue lasers and laser beams having higher power andhigh beam qualities, for use in among other things improved additivelaser manufacturing process, welding processes, cutting processes,brazing processes, polishing processes, ablation processes and solderingprocesses. The present inventions, among other things, solve these needsby providing the articles of manufacture, devices and processes taught,and disclosed herein.

There is provided a laser additive manufacturing (LAM) apparatus having:a laser for providing a functional laser beam along a beam path, thefunctional laser beam having a wavelength less than about 750 nm; abuild table; a starting material, and a starting material deliveryapparatus, wherein the starting material can be delivered to a targetarea adjacent the build table; a laser beam delivery apparatus, having abeam shaping optic to provide a functional laser beam and form a laserbeam spot; a motor and positioning apparatus, mechanically connected tothe build table, the laser beam delivery apparatus, or both; whereby themotor and positioning apparatus are capable of providing relativemovement between the laser beam delivery apparatus and the build table;and, a control system, the control system having a processor, a memorydevice and a LAM plan, wherein the control system is capable ofimplementing the LAM plan through the predetermined placement of thefunctional laser beam and the starting material.

Yet further there is provided systems, apparatus and methods that haveone or more of the following features: wherein the laser has a pumplaser diode having a wavelength of less than 500 nm and a Ramanoscillator fiber; wherein the laser has a pump laser diode and a Ramanoscillator that are configured to provide an n-order Raman oscillation,where n is an integer; wherein n is selected from the group consistingof 1, 2, 3, 4, 5, 6, 7, 8 and 9; wherein the n-order oscillation isstokes; wherein the n-order oscillation is anti-stokes; wherein thebuild material is selected from the group consisting of Magnesium,Aluminum, Gallium, Tin, Lead, Titanium, Vanadium, Chromium, Manganese,Iron, Cobalt, Nickel, Copper, Zinc, Zirconium, Molybdenum, Rhodium,Palladium, Silver, Cadmium, Tungsten, Gold, Mercury, metals, alloys ofmetals, and mixtures of metals; wherein the starting material is apowder; wherein the starting material is a powder having a particle sizeless than about 1 μm; wherein the starting material is a powder having aparticle size from about 0.05 μm to about 2.5 μm; wherein the startingmaterial is a powder having a particle size from about 0.05 μm to about2.5 μm; wherein the starting material is a powder having a particle sizefrom about 40 μm and smaller; wherein the starting material is a powderhaving a particle size less than about 25 μm; wherein the startingmaterial is a powder having a particle size less than about 15 μm; andwherein the starting material is a powder having a particle size lessthan about 0.5 μm.

Additionally, there is provide a Raman laser modules (RLM) for use inlaser additive manufacturing, the RLM having: a pump laser beam sourceand a Raman oscillator for providing a functional laser beam; thefunctional laser beam having a wavelength less than about 700 nm, a M²of less than 2, and a power of greater than 500 W.

Still further there is provided apparatus, systems and methods havingone or more of the following features: wherein the Raman oscillator hasa fiber oscillator having a material selected from the group consistingof Silica, GeO₂ doped silica, Phosphorus doped silica; wherein the pumplaser source has a diode laser; wherein the pump laser source has aplurality of laser diodes to produce a pump laser beam having a beamparameter product of less than about 10 mm-mrad; wherein the pump lasersource has an array of at least 20 blue laser diodes; wherein the arrayprovides a pump laser beam having a wavelength in the range of about 405nm to about 460 nm; wherein the oscillator fiber has a length and thelength is about 30 m or less; wherein the oscillator fiber has a lengthand the length is about 20 m or less; wherein the oscillator fiber has alength and the length is about 25 m or less; wherein the oscillatorfiber has a length and the length is about 40 m or less; and wherein thefunctional laser beam has a wavelength from about 405 nm to about 470nm.

Furthermore, there is provided apparatus, methods and systems whereinthe pump laser source has a blue laser diode system, the systemproviding a pump laser beam having a wavelength of about 405 nm-475 nm,a power of greater than 100 W; and wherein the Raman oscillator fiberhas a core diameter of about 10 μm-50 μm and is a graded index fiber ora step index fiber.

Yet additionally there is provided a means to cool the lasers, includingthe pump laser source, which cooling means can be air cooling usingactive or passive air cooling, liquid cooling, such as using a coolantor refrigerant, and water cooling, such as using a closed loop watercooling system.

Furthermore, there is provided apparatus, methods and systems having oneor more of the following features: wherein the pump laser source has aspectral beam combiner; wherein laser beams from the RLMs are coherentlycombined to form a single functional laser beam; wherein the pump lasersource has a laser diode and integral drive electronics to control thecurrent and enable the rapid pulsing of the pump laser source diode toprovide a pulsed pump laser beam; and wherein the pulse rate to fromabout 0.1 MHz to about 10 MHz.

Still further, there is provide a 3-D printing apparatus having astarting material delivery apparatus, wherein a starting material can bedelivered to a target area adjacent a predetermined build area; a beamshaping optic to provide a functional laser beam spot having a crosssection of less than about 100 microns at the build area; and a Ramanlaser module (RLM).

Yet further, there is provided a LAM system, including a 3-D printingapparatus having a RLM one or more of the RLMs described in thisspecification.

Additionally, there is provided a method of laser additive manufacturing(LAM), the method including: providing a starting material, the startingmaterial having a predetermined maximum absorption wavelength; directinga functional laser beam having a predetermined wavelength to thestarting material, the functional laser beam wavelength being based atleast in part to match the starting material maximum absorptionwavelength; the functional laser beam interacting with the startingmaterial to build an article.

Moreover, there is provided methods, systems and apparatus having one ormore of the following features: wherein the functional laser beamwavelength and the maximum absorption wavelength are matched within 100nm of each other; wherein the functional laser beam wavelength and themaximum absorption wavelength are matched within 50 nm of each other;wherein the functional laser beam wavelength and the maximum absorptionwavelength are matched within 10% of each other; wherein the functionallaser beam wavelength and the maximum absorption wavelength are matchedwithin 20% of each other; wherein the functional laser beam wavelengthand the maximum absorption wavelength are matched, wherein they are thesame wavelength; wherein the article is built in a single step; whereinthe article has: a Thermal Expansion μm/(m-K)(at 25° C.) of 7.5 to 32;Thermal Conductivity W/(m-K) of 18 to 450; Electrical Resistivity nΩ-m(at 20° C.) of 14 to 420; Young's Modulus GPa of 40 to 220; ShearModulus GPa of 15 to 52; Bulk Modulus GPa 40 to 190; Poisson ratio of0.2 to 0.5; Mohs hardness of 1 to 7; Vickers hardness MPa of 150 to3500; Brinell hardness MPa 35 to 2800; Density g/cm³ 1.5 to 21; whereinthe article has: a Thermal Expansion μm/(m-K)(at 25° C.) of 7.5 to 32;Thermal Conductivity W/(m-K) of 18 to 450; Young's Modulus GPa of 40 to220; Shear Modulus GPa of 15 to 52; Bulk Modulus GPa 40 to 190; Poissonratio of 0.2 to 0.5; and Density g/cm³ 1.5 to 21; wherein the articlehas: Electrical Resistivity nΩ-m (at 20° C.) of 14 to 420; Poisson ratioof 0.2 to 0.5; and Mohs hardness of 1 to 7; wherein the article has: aThermal Expansion μm/(m-K)(at 25° C.) of 7.5 to 32; ElectricalResistivity nΩ-m (at 20° C.) of 14 to 420; Young's Modulus GPa of 40 to220; Mohs hardness of 1 to 7; and Density g/cm³ 1.5 to 21; and whereinthe article has a physical property selected from the group consistingof: a Thermal Expansion μm/(m-K)(at 25° C.) of 7.5 to 32; ThermalConductivity W/(m-K) of 18 to 450; Electrical Resistivity nΩ-m (at 20°C.) of 14 to 420; Young's Modulus GPa of 40 to 220; Shear Modulus GPa of15 to 52; Bulk Modulus GPa 40 to 190; Poisson ratio of 0.2 to 0.5; Mohshardness of 1 to 7; Vickers hardness MPa of 150 to 3500; Brinellhardness MPa 35 to 2800; and Density g/cm³ 1.5 to 21.

Yet moreover, there is provided apparatus, systems and methods havingone or more of the following features: wherein the Raman oscillator hasa crystal oscillator having material selected from the group consistingof Diamond, KGW, YVO₄, and Ba(NO₃)₂; wherein the Raman oscillator has ahigh pressure gas; wherein the pump laser source has a plurality oflaser diodes to produce a pump laser beam having a beam parameterproduct of less than about 14 mm-mrad; and wherein the pump laser sourcehas a plurality of laser diodes to produce a pump laser beam having abeam parameter product from about 9 to about 14 mm-mrad.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of an embodiment of a LAM systemand process in accordance with the present inventions.

FIG. 2 is a cross sectional view of an embodiment of starting materialin a stage of a LAM process in accordance with the present inventions.

FIG. 2A is a cross sectional view of an embodiment of an article formedfrom the starting material of FIG. 2 in a later stage of an embodimentof the LAM process in accordance with the present inventions.

FIG. 2B is a cross sectional view of embodiment of starting material andthe article of FIG. 2A in a later stage of an embodiment of the LAMprocess in accordance with the present inventions.

FIG. 3 is a cross sectional view of an embodiment of a LAM article inaccordance with the present inventions.

FIG. 4 is a cross sectional view of an embodiment of a LAM article inaccordance with the present inventions.

FIG. 5 is a perspective view of a LAM system in accordance with thepresent inventions.

FIG. 6 is a perspective view of a LAM system in accordance with thepresent inventions.

FIG. 7 is a chart of output vs output coupler percentage for variousRaman oscillator fiber lengths to provide a 459 nm functional laser beamin accordance with the present inventions.

FIG. 8 is a chart of output power vs output coupler percentage atvarious 100 W pump wavelengths to provide a 455 nm functional laser beamin accordance with the present inventions.

FIG. 9 is a chart of output power vs output coupler for a 455 nmfunctional laser beam from a 100 W 450 nm pump laser beam at variousRaman oscillator fiber lengths in accordance with the presentinventions.

FIG. 10 is a chart of spot size vs beam waist, for a pump laser beamthrough a 500 mm focal length lens for the slow axis and the fast axisof a collimated laser diode in accordance with the present inventions.

FIG. 11 is a chart showing maximum absorption wavelengths forembodiments of starting materials for use in accordance with the presentinventions.

FIG. 12 is a chart showing absorption of water for use in accordancewith the present inventions.

FIGS. 13A to 13C are charts showing Raman stokes shifts and Ramancascades for Raman fibers and Raman Crystals of various materials inaccordance with the present inventions.

FIGS. 14A to 14C are charts showing Raman anti-stokes shifts and Ramancascades for Raman fibers and Raman Crystals of various materials inaccordance with the present inventions.

FIG. 15 is the Raman spectra in an embodiment of a phosphosilicate fiberfor three different dopant levels for use in accordance with the presentinventions.

FIG. 16 is graph of the absorption of various metals showing inincreased absorption at the wavelengths for embodiments of a laser inaccordance with the present inventions.

FIG. 17 is a schematic view of of an embodiment of a LAM system inaccordance with the present inventions.

FIG. 18 is graph showing the laser performance of various embodiments oflasers in accordance with the present inventions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In general, the present inventions relate to lasers that produce laserbeams having wavelengths in about the 200 nm to 800 nm range. Inparticular, embodiments of the present inventions relate to lasers thatproduce blue laser beams and applications for these laser beams.Further, embodiments of the present inventions relate to higher power,and high power, lasers and laser beams having wavelengths in the 300-700nm ranges, and in particular in the 400s nm range and in the 500s nmrange; and such lasers and laser beams in these wavelengths havingexcellent beam qualities. Embodiments of the present inventions furtherrelate to additive manufacturing and laser material processing, and inparticular laser additive manufacturing processes as well as welding,brazing, cutting and soldering, using the novel laser beams of the novellasers of the present inventions.

Further, embodiments of the present inventions relate to predeterminedmetallic starting materials and predetermined laser wavelengths toperform laser additive manufacturing on these starting materials. Inparticular, embodiments of the present inventions relate topredetermined laser beam wavelengths matched to metallic startingmaterials to perform laser additive manufacturing to make metallicarticles.

Turning to FIG. 1 there is shown a schematic diagram illustrating anembodiment of a LAM system and process. Thus, there is a base 100, alaser unit 101, a laser beam delivery assembly 102. The laser beamdelivery assembly 102 has a distal end 108 that is at a stand offdistance 103 from the base 100 (and at a stand off distance from thestarting material, when starting material is present on the base).Typically during a LAM process starting material (not shown in thefigure) is supported by the base 100. The starting material and thelaser beam are then moved relative to each other as the functional laserbeam 109 travels along beam path 110, to form a laser spot 111 thatcontacts the starting material, and joins the starting material togetherto form an article. The relative motion (e.g., raster scan) of thestarting material and the laser spot is illustrated by arrows 104 (e.g.,x-axis motion), 105 (e.g., y-axis motion), 106 (e.g., z-axis motion),and 107 (e.g. rotation), additionally the angle at which the laser beampath and the laser beam strikes the base, and thus the starting materialon the base, can be changed. The laser spot may also be moved in avector fashion, where both x and y motion occur simultaneously movingthe spot to a predetermined position on the material. The angle of thelaser beam on the target in FIG. 1 is at 90° or a right angle to thebase. This angle can be varied from 45° to 135°, from 30° to 120°, andfrom 0° to 180°, and from 180° to 360° (e.g. the article is inverted tomake, for example, a U shaped lip.) Further combinations and variationsof these different basic relative motions can be performed, incoordination with the firing of the laser beam and deposition ofstarting material, and in this manner articles of many different shapes,sizes and with varying degrees of complexity can be made. It beingunderstood that these relative motions can be achieved by moving thebase, moving the laser delivery assembly, steering the laser beam (e.g.,scanning the beam with galvo-scanners) and combinations and variationsof these.

The laser unit and the laser beam delivery assembly can be one integralapparatus, or they can be separated and optically connected, for examplevia optical fibers or a flying optic head. Further, some or all of thecomponents of the laser unit can be in the laser beam delivery assembly,and vice versa. Also, these components, and other components, can belocated away from the laser unit and the laser beam delivery assembly.These remote components can be optically associated, functionallyassociated (e.g., control communication, data communication, WiFi, etc.)and both, with the laser unit and the laser beam delivery assembly. Thelaser unit and the laser beam delivery assembly generally have a highpower laser (preferably the Raman lasers disclosed and taught in thisspecification or the direct diode lasers disclosed and taught in Ser.No. 62/193,047 the entire disclosure of which is incorporated herein byreference) and beam shaping and handling optics to deliver the laserbeam along a laser beam path in a predetermined spot size.

Preferably, the laser unit has a high power laser that is capable ofgenerating, and propagating, a laser beam in a predetermined wavelengthand delivers the laser beam to the laser beam delivery assembly, whichcan shape and deliver the laser beam from the distal end along the laserbeam path to the target, e.g., the starting material, which could be onthe base or on an article being built.

For example, the laser beam can preferably have one, two, or more of theproperties that are set forth in Table I. (A column, or a row, in thetable are not for a specific embodiment; and thus, different rowproperties can be combined with different column properties, e.g., apower in one column could be present for all of the differentwavelengths. Thus, a single embodiment may have properties fromdifferent columns and different rows of the table.)

TABLE I Range Examples in range Wavelength nm 375-600 405 445 447 450455 450 520 532 635 Power kW 0.5-10+ 1 1.5 2 2.25 2.5 2.75 3 4 5Continuous Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Modulation 0-2 MHz 2MHz 2 MHz 2 MHz 2 MHz 2 MHz 2 MHz 2 MHz 2 MHz 2 MHz Bandwidth M² 1-501.05 1.5 1.75 2 4 10 15 20 25 Beam parameter 0.3  0.32 0.45 0.53 0.6 1.23 4.5 8 7.5 product mm mrad Beam waist 10 μm 10 μm 10 μm 10 μm 10 μm 10μm 10 μm 10 μm 10 μm 10 μm Numerical Aperture 0.03 0.032 0.045 0.53 0.060.12 0.3 0.45 0.6 0.75 Single Transverse Yes Yes Yes Yes Yes Yes Yes YesYes Yes Mode Multi Transverse Yes Yes Yes Yes Yes Yes Yes Yes Yes YesMode Spot size cross ~0.5-300+ 1 2 5 10 15 30 40 60 100 section* μm*cross section is the longest distance across the spot, e.g., slow axis;for a circular spot the cross section is the diameter; for an ellipse itwould be the major axis.

The laser beam deliver apparatus contains passive and active laser beamshaping optics to provide a predetermined spot size at the intendedstand off distance. The laser beam delivery apparatus can also contain,or have operably associated with monitoring and control devices. Forexample, the device could have down the pipe viewing with for example ahigh speed video camera. In this manner the camera looks down the laserbeam path to the base and can view the formation of the melt puddle fromthe laser beams interaction with the starting material. Depth sensors orgauges, location sensors or gauges, laser monitory, Infrared and visiblepyrometers for measuring the melt puddle temperature and measuringdevices, and other monitoring, analysis and control apparatus may beused. In this manner the LAM process, e.g., the process of building ormaking the article from the starting material can be monitored, analyzedand controlled. Thus LAM process can be controlled to follow apredetermined application, it can be changed or modified in real-time orthe monitoring equipment can provide real time feedback on thedensification and quality of the material being processed.

A delivery device for providing the starting material may also be in,adjacent to, or otherwise operably associated with the laser beamdelivery apparatus, or otherwise associated with it. In this manner thestarting material can be delivered, e.g., sprayed, flowed, conveyed,drawn, poured, dusted, on to the base or on to the article being made.Thus, for example the starting material can be delivered through a jet,a nozzle, a co-axial jet around the laser beam, an air knife or doctorblade assembly, any apparatus to deliver the starting material ahead ofthe movement of the laser beam, spray nozzles, and other devices fordelivering and handling the starting material. For example, startingmaterial delivery devices, and processes for delivering startingmaterials, that are found in 3-D printing applications can be used.

Embodiments of 3-D printing apparatus systems and methods are disclosedand taught in U.S. Pat. Nos. 5,352,405, 5,340,656, 5,204,055, 4,863,538,5,902,441, 5,053,090, 5,597,589, and US Patent Application PublicationNo. 2012/0072001, the entire disclosure of each of which is incorporatedherein by reference.

A control system preferably integrates, monitors and controls theoperation of the laser, the movement of various components to providefor the relative movement to build the article, and the delivery of thestarting material. The control system may also integrate, monitor andcontrol other aspects of the operation, such as monitoring, safetyinterlocks, laser operating conditions, and LAM processing programs orplans. The control system can be in communication with, (e.g., via anetwork) or have as part of its system, data storage and processingdevices for storing and calculating various information and datarelating to items, such as, customer information, billing information,inventory, operation history, maintenance, and LAM processing programsor plans, to name a few.

A LAM processing program or plan is a file, program or series ofinstructions that the controller implements to operate the LAM device,e.g., a 3-D printer, to perform a predetermined LAM process to make apredetermined article. The LAM processing plan can be, can be basedupon, or derived from, a 3-D drawing or model file, e.g., CAD files,such as files in standard formats including, for example, .STEP, .STL,.WRL (VRML), .PLY, .₃DS, and .ZPR. The controller has the LAM processingplan (e.g., in its memory, on a drive, on a storage device, or availablevia network) and uses that plan to operate the device to perform the LAMprocess to build the intended article. The controller may have thecapability to directly use the 3-D model file, or convert that file to aLAM processing plan. The conversion may be done by another computer, andmade directly available to the controller, or held in memory, or on astorage device, for later use. An example of a program to convert a 3-Dmodel file to a LAM processing plan is ZPrint™ from Z Corp.

The starting materials can be liquids, fluids, solids,inverse-emulsions, emulsions, colloids, micro-emulsions, suspensions, toname a few, and combinations and variations of these. Fluid basedstarting material systems, e.g., suspensions, colloids, emulsions, havea carrier component and a building component dispersed within thecarrier component. The build component interacts with the laser beam tomake the article. These starting material systems can have a carriercomponent that is transmissive to the laser wavelength and a buildcomponent that is absorptive to the laser wavelength. Turning to FIG. 11and FIG. 12 there is shown the absorption characteristics of examples ofmetallic starting materials, e.g., build materials, and the absorptioncharacteristics of an example of a carrier component, water. It can beseen from these figures that at the 450 nm wavelength the buildcomponents are highly absorptive while water is readily transmissive tothat wavelength. Thus, for fluid based starting material systems, for apredetermined laser wavelength, and in particular the laser wavelengthsof Table I, the build component can have an absorption that is at least2× the absorption of the carrier component, at least 5× the absorptionof the carrier component, at least 10× the absorption of the carriercomponent, and at least 100× the absorption of the carrier component.

Turning to FIG. 16 there is shown the absorption characteristics forAlumina, Copper, Gold, Silver, Titanium, Iron, Nickel, Stain Steel 304,and Tin, which can be the bases of, or constitute starting materials.From this graph it is seen that at the wavelengths for embodiments ofthe present lasers, e.g., line 1602, the absorption for these metals isgreater than their absorption at IR wavelengths, e.g., line 1601.

Preferably, for the wavelengths of Table I, the starting materials aremetal based particles, e.g., beads, powder, particulate. Thus,embodiments of the starting material can be particles of Magnesium,Aluminum, Gallium, Tin, Lead, Titanium, Vanadium, Chromium, Manganese,Iron, Cobalt, Nickel, Copper, Zinc, Zirconium, Molybdenum, Rhodium,Palladium, Silver, Cadmium, Tungsten, Gold, and Mercury, alloys of theseand other metals, Inconel 625, Invar, Stainless Steel, Stainless Steel304 and mixtures and variations of these and other metals and alloys.Embodiments of the starting materials may be, or include: ceramicmaterials, such as Silicon Carbide, photo-structurable, aluminosilicateglass-ceramic substrates; Aluminum filled plastics; impact resistantNylon; Nylon; glass filled Nylon; Flame retardant Nylon; Carbon fiber;Carbon fiber filled Nylon; and Rubber-like plastics, to name a few.Embodiment of systems can also include a flowing gas air knife to insurethe optical system remains clean as well as provides a means to captureany volatiles released during the processing of the materials. Theparticles may also contain metals and other materials such as a ceramicor filler, for example to make a mixed metal complex article or acomposite article. Other types of starting materials known to the 3-Dprinting arts may also be used. Preferably, the functional laser beamwavelength can be matched, e.g., predetermined, to the absorptioncharacteristics of the starting material. Thus, for example, embodimentsof starting materials having good to high absorption at 450 nm are shownin FIG. 11 and which are also shown in FIG. 16.

The metallic particles may be incorporated, and preferably, evenlydistributed into a fiber or rod, for feeding into the path of the laserbeam to build an article. Preferably the carrier for the metallicparticles in the fiber or rod, can be incorporated into the alloy beingformed establishing the correct ratio of each metal with the metal“tubing” providing the necessary balance of materials in the meltpuddle. Additionally, the fiber or rod carrier could be a non-metallicmaterial which is vaporized by the functional laser beam, removed by theair knife system, with minimal, negligible or no effect on the startingmaterials or the built article. The carrier material may also beselected to form a part of the article, such as a composite article. Forexample the functional laser beam may have absorption characteristicsthat provide for the fusing of the metal particles creating a matrix forthe article that is then filled in with the carrier material.

The novel and new lasers and high power laser beams provide manyopportunities for these types of predetermined starting materialcombinations to take advantage of different absorption characteristicsand build materials and articles that were not obtainable with prior 3-Dprinting, and which were not generally obtainable at wavelengths belowabout 700 nm. Further, if the metal particles are in the sub-micronrange there is provided the ability to build unique and newnano-composite articles and nano-composite materials.

It should be understood that an article, and a built or made article,can be, for example, a finished end product, a finished component foruse in an end product, a product or component that needs furtherprocessing or additional manufacturing steps, a material for use inother applications, and a coating on a substrate, for example a coatingon a wire.

The particles of the starting material can be composed entirely of asingle metal or a single alloy, can be composed entirely of a mixture ofseveral metals, alloys and both, can be composed of from about 5% toabout 100% of a metal, an alloy, or both. The metal based component ofthe starting material particle can be located on the exterior of theparticle, so as to be directly contacted by the laser beam and so as tobe available for joining particles together. The particles can be thesame shape, essentially the same shape or they can be different shapes.The particles can be essentially the same size or they can be differentsizes. The particles can have cross sections from about <1 μm to about 1mm, about 1 μm to about 100 μm, about 1 μm to about 5 μm, about 0.05 μmto about 2.5 μm, about 0.1 μm to about 3.5 μm, about 0.5 μm to about 1.5μm, about 1 μm to about 10 μm, about 0.1 μm to about 1 μm, and largerand smaller sizes. The particle size, e.g., cross section, can have apredetermined size with respect to a predetermined functional laser beamwavelength. Thus, for example the particles can have a size that isabout 1/10 of the laser beam spot size, the same as the laser beamwavelength, 2× larger than the wavelength, 3× larger than thewavelength, 5× larger than the wavelength, and 10× larger than thewavelength, as well as, smaller and larger sizes. Preferably, the use ofparticles having a size smaller than the laser beam spot and a laserbeam spot about the same size of the laser beam, e.g., a single modediffraction limited beam forming its smallest spot, can provide veryhigh resolution articles, e.g., high resolution 3-D printing.

The particle size and shape can be predetermined with respect to apredetermined functional laser beam spot. Thus, for example theparticles can have a size that is smaller than the laser beam spot(e.g., ½, ⅕, 1/10), that is about the same as the laser beam spot, 2×larger than the spot, 3× larger than the spot, 5× larger than the spot,and 10× larger than the spot. The particles can have shapes that areessentially the same as the shape of the laser beam spot, e.g.,spherical beads for a circular spot, or that are different, andcombinations and variations of these.

For a batch of particles in a starting material that has a particle sizedistribution, when referring to the size of the particles the medianparticle size distribution, e.g., D₅₀, can be used. Typical 3-D printingmachines have an average particle size of 40 μm with the particlesranging in size from 15 μm to 80 μm. Particle distributions that aremore tightly controlled are preferred and will improve the surfaceroughness of the final printed part.

The shape of the particles in the starting material can be anyvolumetric shape and can include for example, the following: spheres,pellets, rings, lenses, disks, panels, cones, frustoconical shapes,squares, rectangles, cubes, channels, hollow sealed chambers, hollowspheres, blocks, sheets, coatings, films, skins, slabs, fibers, staplefibers, tubes, cups, irregular or amorphous shapes, ellipsoids,spheroids, eggs, multifaceted structures, and polyhedrons (e.g.,octahedron, dodecahedron, icosidodecahedron, rhombic triacontahedron,and prism) and combinations and various of these and other more complexshapes, both engineering and architectural. The preferred particlesshape is essentially nearly perfect spheres, with a narrow sizedistribution, to assist in the flowing of the particles through thesystem as well as reducing the surface roughness of the final partproduced. Any shape that reduces the stiction, friction and both,between particles is preferred when the average particle size is smallerthan 40 μm.

Turning to FIG. 2 to 2B there is shown a schematic representation of anembodiment of a LAM process. In FIG. 2 there is shown a simplifiedschematic of several starting material particles, e.g., 201, 202, 203forming two layers 204, 205. In operation the function laser beaminteracts with the starting material particles fusing them together toform, as is seen in FIG. 2A, an initial section 206 of the article 207.In FIG. 2B, an additional layer 208 of starting material particles,e.g., 209, is placed on the initial section 206. The functional laserbeam then fuses the additional layer 208 with the initial section 206,further building the article 207. This process is then repeated untilthe article is completed.

In the embodiment of the process and article of FIG. 2 to 2B the articleis build as an essentially solid monolithic material, as shown forexample in initial section 206. The LAM devices and process, and inparticular LAM devices using the laser beams of Table I have the abilityto make articles that are exceeding strong without the need for aseparate infiltration, or resin infiltration step, to strengthen thearticle. Thus, embodiments of the present LAM devices and processes canmake articles in a single step (i.e., without a subsequent infiltrationprocess, filling, or refilling type process) that can be 2×, 3×, 4×, 10×or more stronger that articles made by a single process, as well asarticles made by a two step reinfiltration process, with current 3-Dprinters. Thus, embodiments of the present LAM built, e.g., 3-D printed,articles of the present inventions can have the properties that are setout in Table II.

TABLE II Thermal Expansion Thermal Electrical Young's Shear Bulk VickersBrinell Embodiment μm/(m-K) Conductivity Resistivity Modulus ModulusModulus Poisson Mohs hardness hardness Density of an Article (at 25° C.)W/(m-K) nΩ-m (at 20° C.) GPa GPa GPa ratio hardness MPa MPa g/cm³ 1 8.621.9 420 116 44 110 0.32 6.0  830-3420  716-2770 4.506 2 23.1 237 28.270 26 76 0.35 2.75 160-350 160-550 2.70 3 18.9 429 15.87 83 30 100 0.372.5 251 206-250 10.49 4 14.2 318 22.14 79 27 180 0.4 2.5 188-216 188-24519.30 5 22.0 66.8 115 50 18 58 0.36 — —  50-440 5.769 6 11.8 80.4 96.1211 82 170 0.29 4 608  200-1180 7.874 7 24.8 156 43.9 45 17 45 0.291-2.5 —  44-260 1.738 8 30.2 116 59.0 108 43 70 0.25 2.5 — 327-412 7.149 16.5 401 16.78 126 48 140 0.34 3.0 343-369 235-878 8.96

Embodiments of LAM built articles and materials, and in particular,articles that are build by a single step 3-D printing process can have,one or more of the following properties: Thermal Expansion μm/(m-K)(at25° C.) of 0 to 32; Thermal Conductivity W/(m-K) of 18 to 450;Electrical Resistivity nΩ-m (at 20° C.) of 14 to 420; Young's ModulusGPa of 40 to 220; Shear Modulus GPa of 15 to 52; Bulk Modulus GPa 40 to190; Poisson ratio of 0.2 to 0.5; Mohs hardness of 1 to 7; Vickershardness MPa of 150 to 3500; Brinell hardness MPa 35 to 2800; Densityg/cm³ 1.5 to 21, and combinations of these and other features andproperties.

Turning to FIG. 3 there is shown an embodiment of an article, in theform of a built skeleton 301, of metal starting materials that can beformed by selectively fusing metal starting materials using a functionlaser beam pursuant to a LAM processing plan. The skeleton 301 hasinterconnected filaments, e.g., 302, 303 and voids, e.g., 304. FurtherLAM processes or other process may be performed on this article 301, orit may be a finished article, e.g., a filter.

Turning to FIG. 4, there is shown an embodiment of a built article 400that is made up of several different size starting material particles,e.g., 401, 403, 404. The particles are fused together at joints, e.g.,405, 406, 407 and form voids, e.g., 408. Further LAM processes, or otherprocess, may be performed on this article 400, or it may be a finishedarticle.

Turning to FIG. 5 there is shown a perspective view of an embodiment ofa LAM system 500. The system 500 has a cabinet 501 that contains thelaser unit, the laser beam delivery assembly and the base. The cabinet501 also contains the motors, sensors, actuators, nozzles, startingmaterial delivery devices, and other devices used to perform therelative motion and to deliver the starting material in a predeterminedmanner, e.g., the equipment and devices to implement the LAM processingplan. The cabinet 501, and more specifically the components within thecabinet 501, are in data and control communication with an operationstation 502, having a controller, via cable 503. The controller can be aPLC (programmable logic controller), an automation and devicecontroller, a PC, or other type of computer that can implement the LAMprocessing plan. In this embodiment the operation station has two GUI(graphic user interfaces) 503, 504, e.g., monitors. The cabinet 501 hasan access panel 505, which may be a window having laser safe glass.

In embodiments of the LAM system, the system, and preferably thecabinet, can contain the following additional components: automatic airfilters, starting material bulk storage, compressor for delivering airto clean the finished article, internal filtering system to enable thebuild area (e.g., the location where the functional laser beam isinteracting with and fusing the starting materials) to remain clean andfree of dust or other materials that would interfere with the laserbeam's travel along the laser beam path. Further, the controller can belocated in the cabinet, adjacent to the cabinet, or in a remotelocation, but in control and data communication with the system. Oxygenmonitors in both the build chamber and filter can also be used, andpreferably are used, to continuously monitor the absence of oxygen.

Turning to FIG. 6 there is provided a perspective view of a LAM buildarea 600. The build area 600 has a build table 601 that has a drivemotor 602, which is connected to the table 601 by articulated robot 603.In this manner the motion of the table, turning, angle, standoffdistance can be controlled. A starting material delivery assembly 604has a starting material feed line 605 and a nozzle 606 positionedadjacent the location where the laser beam 608 is targeted. The laserbeam 608 is delivered from the laser head 614. The laser head 614 has acamera 611 for viewing the LAM process, a connector 612 and opticalfiber 613 for delivering the functional laser beam from the laser unit,and beam shaping optics assembly 607, e.g., focusing optics, fordelivering the laser beam 608 along a laser beam path 616 to the targetarea 617. The laser head 614 has two laser position determining devices,609, 610 which use laser beams to measure and monitor the position sizeand shape of the article as it is built during the LAM process. Thelaser head 614 has a mount 615 that is connected to a frame not shown.The frame and the drive motor 602 may also be integral and movable toprovide additional types of relative motion.

The lower wavelengths ranges, e.g. about 700 nm and below providesignificant advantages in LAM and in particular 3-D printing. In theselower wavelength ranges the higher absorptivity of the startingmaterial, and in particular metallic and metal based, starting materialsprovides, among other things, the ability to perform LAM processes atgreater efficiencies. For example, because of the high absorptivity,less laser power is needed to perform the joining of the startingmaterials to build an article. This can result in faster build times,less expensive LAM devices, LAM devices requiring less maintenance andhaving longer duty cycles, among other advantages.

For example embodiments of 3-D printers, building metal articles, canhave linear print speeds of greater than 1 m/sec., greater than 5m/sec., and greater than 10 m/sec. Further, and in general dependingupon the particular material, a blue laser can cut 2 mm or thinner metalsheets at least about 4× faster than a CO₂ laser and at least about 2×faster than a fiber laser. Viewed differently, this enables a 2 kW bluelaser to have the same cutting rates for these materials as a 5-8 kW CO₂laser. The increased absorption of the blue laser light is an advantageand preferred where an adiabatic process dominates the laser processsuch as is the case of cutting, welding, and sintering thin materials.This advantage is less utilized, or provides a smaller benefit, formaterials that are 5 mm or thicker where the process if limited by thethermal diffusivity of the material being processed and as aconsequence, the absorption properties have less of an effect on theprocess than just the total power being used.

Additionally, the lower wavelengths provide the ability to havesubstantially smaller spot sizes and greater control over the buildingprocess. In this manner articles with sharper edges, smoother surfaces,and having highly refined surface features and properties, equal tothose of finely machined parts are obtainable with the present LAMsystems. Fundamentally, the spot size formed by the laser is limited bythe wavelength of the source laser, the shorter the wavelength, thesmaller the spot size that is formed for a given focal length system.However, if the same spot size is desired, then a longer focal lengthlens may be used with a blue laser compared to an IR laser, allowing forthe blue laser to provided up to 8× the addressable volume of the IRlaser source.

The spot size of the system combined with the particle size being fuseddetermines the minimum feature size and surface roughness. Using smallerdiameter particles (<40 μ□, <10 μm or <1 μm) with a beam size that is<40 μm, <10 μm or <1 μm can produce a part with a minimum feature sizeson the order of ˜40 μm, ˜10 μm or ˜1 μm resulting in a dramaticimprovement in the surface roughness for the part <1 μm. The smaller thespot, and the smaller the particles that are used to form the part meansthat the shrinkage and stresses in the part can be controlledsignificantly better than with larger particles and as a consequencegreater part stability can be achieved. The smaller, the volume ofmaterial processed, the less energy that is required to melt the“voxel”, as a consequence the substrate, or part under construction willexperience a lower thermal gradient during fabrication and as aconsequence, a lower amount of shrinkage as the part “cools” from itsprocessing temperature. Thus, by using less laser power, e.g., lowerheat input, to fuse particles into a solid, greater strength and lowerwarpage of the article being built can be achieved.

Embodiments of the present lasers provide laser beams in the 300 nm to800 nm range. Embodiments of the Raman lasers of the present inventionsprovide laser beams having wavelengths in the 300-700 nm range, and inparticular having wavelengths in the 400s nm range and in the 500s nmrange. Embodiments of the present Raman lasers have powers of at leastabout 10 W (0.01 kW), at least about 100 W (0.1 kW), at least about1,000 W (1 kW), at least about 5 kW and greater. Additionally, the Ramanlasers and laser beams of the present inventions have excellent beamquality. Thus, embodiments of these Raman generated laser beams can havethe beam parameter scalability shown in FIG. 18. This Figure highlightsthe beam parameters that can be generated with a direct blue laser diodesource (450 nm) line 1801, a wavelength combined blue laser diode sourceline 1802, a Raman laser source that is optically combined line 1803,and a wavelength combined blue Raman Laser source line 1804. The Ramanlaser source provides source brightness that is superior to IR lasers ofsimilar power output. The wavelength combined Raman source providesunprecedented power and beam brightness across a wide range of outputpower levels. The Raman laser source can have a scalability similar tothe wavelength combined Raman laser source with the development of largecore optical fibers capable of maintaining single mode performance overa wide spectral range (˜10 μm for fused silica).

It should be noted that, although the primary focus in thisspecification is on applications using the Raman high power blue lasersof the present inventions in LAM processes, systems and devices, thereare many present, and future, applications for the Raman lasers of thepresent inventions. Thus, for example, embodiments of the Raman lasersof the present invention can find application in: welding, cutting, heattreating, brazing and surface modification; to pump an n-Raman orderfiber laser to achieve any visible wavelength; to provide a blue Ramanlaser beam, having at least about 10 W of power for combination with adigital mirror device for projecting a color image including 3-Dcapability; to provide a blue Raman laser beam, having at least about 10W of power for entertainment purposes; to provide a blue Raman laserbeam, having at least about 10 W of power for pumping a phosphor forproducing a white light source that can be used in, among other things,projection systems, headlights, or illumination systems; to provide ablue Raman laser beam, having at least about 10 W of power forunderwater laser range-finding; to provide a blue Raman laser beam,having at least about 10 W of power for underwater communications,including encrypted communications; to provide a blue Raman laser beam,having at least about 10 W of power for laser range finding, and inparticular laser range finding in high water content environments, suchas fog and clouds; to provide a blue Raman laser beam, having at leastabout 10 W of power for communications, and in particular encryptedcommunications in high water content environments, such as fog andclouds; to provide a blue Raman laser beam, having at least about 1000 Wof power for use as a laser weapon underwater, and in high water contentenvironments, such as fog and clouds; to provide a blue Raman laserbeam, having at least about 10,000 W of power for ship and off shoresalvage operations, and in particular surface, tidal and sub-surfaceenvironments; to provide a blue Raman laser beam, having at least about1000 W of power for use as a laser weapon on the ocean, less than a fewfeet above the ocean, through waves in the ocean, and below the surfaceof the ocean; to provide a blue Raman laser beam, having at least about1000 W of power for use as a non-lethal laser weapon; to provide a blueRaman laser beam, having at least about 100 W of power for glasscutting; to provide a blue Raman laser beam, having at least about 1000W of power for removal of paint; to provide a blue Raman laser beam,having at least about 100 W of power for finding diamonds undersea viaRaman scattering; to provide a blue Raman laser beam, having at leastabout 100 W of power for melting AuSn solders and for soldering ingeneral.

Embodiments of the blue Raman lasers of the present invention can findapplication in most present laser cutting, processing and manufacturingsystems. The blue Raman lasers are a ready substitute into thesesystems, replacing the existing IR (infra red, >700 nm) lasers that arepresently used in such systems. The blue Raman laser can provide 2× to10× increases in efficiency, processing speed and other advantages inthese systems over the replaced IR laser. The blue Raman laser can alsoprovided for overall improved systems, having smaller power requirementsand smaller foot prints. Thus, for example, embodiments of the blueRaman laser could be used to replace, e.g., swap out, the IR lasers usedin a laser system in a manufacturing facility, e.g., a large automobilemanufacturing plant. Preferably, this laser swap out can occur withminimal changes to the other components of that laser system such as thebeam delivery optics, which need to be coated for the blue wavelength.

In general, embodiments of the blue Raman lasers of the presentinventions use solid state lasers to pump an n-order Raman laser tooscillate between 410 nm and 800 nm. In an embodiment an array of bluediode lasers, (having at least 10, at least 50, and at least 1000diodes) emitting in the 405-475 nm region can pump an n-order Ramanlaser to oscillate on any orders, e.g., n-Raman orders, between 410 nmto the near infrared 800 nm. It being understood that greater orders orother orders are feasible, and contemplated by the present invention;however, the n-orders in the 405-475 nm range are presently preferred asthere are several commercially available laser diodes available inwavelength pump ranges to provide the n-order Raman ranges.

In an embodiment the blue diode laser array can pump an Anti-StokesRaman laser generating wavelengths as short as 300 nm through n Ramanorders. While the gain for the Anti-Stokes is substantially lower thanfor the Stokes, it is preferable to use a low loss medium whentransitioning from the 450 nm pump wavelength to 300 nm.

In an embodiment the blue laser diode pump is based on individual laserdiodes either in T056 case or individually mounted. Generally, the pumplaser beam from the laser diode is collimated in two axes. The laserdiodes can be placed in a modular package prior to inserting into abackplane, where all of the laser diodes can be co-linear andsimultaneously focused into a single fiber. The laser diodes can also bemounted onto a single carrier, their beams collimated and launched intoa fiber by a single focusing optic. Thus, the laser diode beam can belaunched into a dual clad fiber where the outer clad is 20 μm orgreater, and the inner core is of sufficient diameter to support singlemode operation at the n-th Raman order that will be the output laserwavelength. The ratio of the outer clad to the inner core is limited bythe threshold of the n+1 order, where it is desired to pump the n^(th)order but not the n+1. The n+1 can be suppressed by limiting the ratioof the outer to the inner core, the length of the fiber, or by a filterin the resonator to suppress the n+1 order.

In a preferred embodiment Raman blue lasers of the present inventionsare scalable to 2.9 kW when pumped by a high brightness blue lasersource. At these power levels the conversion efficiency from the bluelaser diode pumps to the 455 nm or 459 nm wavelength can be as high as80%, resulting in a system electrical—optical conversion efficiency of≥20%.

The Raman conversion process is dependent on, and can be highlydependent on, the modal losses of the optical fiber at the bluewavelength. This loss is primarily due to Rayleigh scattering in thefiber and scales according to the inverse fourth power of thewavelength, consequently, the losses at 450 nm can be on the order of 30dB/km. This loss can become a concern, and in some embodiments theprimary concern, when designing the laser system. To address this loss,embodiments of the present Raman laser can use a short optical fiber(e.g., <15 m, <10 m, <5 m, <3 m). These shorter length embodimentsenhance the operational efficiency of the laser. It is understood,however, that longer fibers are contemplated. Thus, Raman oscillatingfibers can be 30 m and greater, 50 m and greater, 80 m and greater, and100 m and greater in length.

Modeling an embodiment of this Raman Laser shows that relatively highoutput coupler reflectivities can be used to achieve a high oscillatingpower level at the first Raman conversion order which results inefficient energy transfer to this order. The energy conversion lossesdue to the Raman shift are nominal since the pump wavelength is 447 nmand the first Raman order can be forced to oscillate at 455 nm. Thiscorresponds to a quantum defect of only 2% with 98% of the energyavailable at the conversion wavelength. However, the Rayleigh scatteringin the fiber limits the conversion efficiency to less than 80% for theshortest fibers modeled (6 m). It being understood that shorter fiberlaser, than this modeled laser are contemplated, and that greater andlesser conversion efficiencies are attainable. Conversely, if theRayleigh scattering can be reduced in an optical fiber, e.g., for a P₂O₅doped fiber which was 85% of the losses of the fused silica fiber, whilethe gain is a factor of 5 higher, then even greater efficiencies can beachieved.

The Raman conversion lasers of the present inventions are capable ofhandling n-Raman orders. This capability can be utilized to design afiber laser output that can oscillate at a predetermined wavelength, andfor example at 455 nm or 459 nm. This embodiment can be designed tooscillate simultaneously at different wavelengths, e.g., at both 455 nmand 459 nm. Preferably, the next Raman order is suppressed. Thissuppression can be achieved, for example, with a good AR coating on thefiber, limiting the length of the fiber and limiting the ratio of theclad to the core, the addition of an in-line lossy filter at the nextRaman order and combinations and variations of these.

In addition to fibers, Raman oscillators can be crystals and gases.Raman crystal oscillators can be, for example, Diamond, KGW, YVO₄, andBa(NO₃)₂. Raman gas oscillators can be, for example, high pressure gasesat pressures of for example 50 atmospheres, high pressure hydrogen, andhigh pressure methane.

By combining a cladding pumped Raman laser with laser diode beamcombining methods enables the design and construction of a multi-kWfiber laser at wavelength in the 400-800 nm range, for example at 455 nmor 459 nm. FIG. 7 is the predicted output for this laser source whenlaunching up to 4,000 Watts of laser diode power into a 200 μm diameterclad with a 30 μm single mode core as a function of the length of thefiber. FIG. 7 shows the power output in W vs % output coupler for Ramanfiber lasers producing 459 nm laser beams from Raman fibers havinglengths of 20 m, 15 m, 10 m, 8 m, and 6 m. These shorter length fiberembodiments have the additional advantage of reducing, mitigating, andpreferably eliminating, adverse consequences from other non-linearphenomenon, such as Stimulated Brillouin Scattering, while suppressingthe next order Raman order oscillation.

In embodiment methods which use a diamond Raman convertor or similarmaterial use a conventional resonator, e.g., a half confocal, or fullconfocal resonator, combined with a mode-matched pump beam. The diamondis unique because of the very large Stokes Shift and high Raman gaincoefficient.

Embodiments of the Stokes Shift for various oscillators are shown inTable III, where the first Stokes shift corresponds to a 29 nm shift inthe wavelength of the light, from 450 nm to 479 nm, one of the largestsingle Stokes shifts feasible with the materials currently availablethat are transparent at this wavelength. Other Raman conversion methodsmay be used to achieved high power visible operation, such as forexample, launching into a pure fused silica fiber, a GeO₂ doped opticalfiber, a P₂O₅ (Phosphorus) doped optical fiber, a KGW crystal pumped byan array of laser diodes or a single laser source, a YVO₄ (YittriumVanidate) crystal pumped by an array of laser diodes or a single lasersource, a Ba(NO₃)₂ (Barium Nitrate) crystal pumped by an array of laserdiodes or a single laser source.

TABLE III 4.50E−05 cm Raman Frequency Shifts Silica GeO2 PhosphorusDiamond KGW YVO4 Ba(NO3)2 Delta Lambda (cm−1) 440 440 1330 1332 901 8921047 1st Stokes 459 459 479 479 469 469 472 2nd Stokes 469 469 511 511490 489 497 3rd Stokes 478 478 548 549 512 512 524 4th Stokes 489 489592 592 537 536 555 5th Stokes 499 499 642 643 564 563 589 6th Stokes511 511 702 703 595 593 627 7th Stokes 522 522 774 775 628 626 671 8thStokes 535 535 863 865 666 663 722 9th Stokes 548 548 975 977 709 705781

An example of the packaging concept for these laser diodes enables avery compact, high density configuration with a highly modular designthat can provide sufficient redundancy for outstanding reliability.Embodiments of the blue diode laser devices oscillate at 450 nm at 20°C. This wavelength can be shifted to lower wavelengths by cooling thediodes, for example the GaN laser diode wavelength shift is on the orderof 0.04 to 0.06 nm/° C. The wavelengths can also be lowered by lockingthe diode with an external grating, such as a Volume Bragg Grating (VBG)or a ruled grating in a Littrow or Littman-Metcalf external cavity. Onlya single VBG is needed to lock the entire pump array to the requisitewavelength. Although two, three or more VBGs may be used. The pumpwavelength can be 450 nm for Raman lasers oscillating at either 455 nmor 459 nm. It should be noted that the 455 nm line has lower gain, thanthe 459 nm line, and results in lower conversion efficiencies.

The blue laser diodes pumps are fiber coupled and fusion spliced to theRaman laser, e.g., the Raman oscillator fiber. This is preferable andprovides the most robust design, capable of operating under extremeconditions such as high vibration and wide temperature swings. It beingrecognized that although preferred for extreme conditions other mannerof coupling the pump laser, and lasers to the Raman oscillator fiberscan be employed such as free space with external optics.

Turning to FIG. 8, there is shown the modeled output of a Ramanoscillator fiber laser having a 62.5 μm diameter clad with a 10 μmdiameter core. The laser has an HR grating at the pump wavelength on thedistal end of the fiber and a HR grating at the first Raman order at thepump input end of the fiber. The reflectivity of the output coupler atthe distal end of the fiber at the first Raman order is varied to studythe dependence on the fiber length and the pump center wavelength.Designs which require high reflectivity at the first Raman order arepreferred for suppression of the second order Raman oscillation but nota requirement. The results for when varying the pump wavelengths from450 nm, 449 nm, 448 nm, and 447 nm coupled into this Raman oscillatorfiber are shown in FIG. 8 for a 455 nm oscillator output thusdemonstrating the pump bandwidth for oscillation at the predeterminedwavelength. In this graph and model, the output power is shown as afunction of the output coupler and the wavelength of the pump source.The fiber is 15 meters in length with a 0.21 na for the 62.5 μm diameterclad. A higher outer cladding na enables even high output power levelsto be injected into the cladding.

The 459 nm Raman laser simulation results are shown in FIG. 9. In thisembodiment the Raman laser is providing a laser beam at 459 nm, wherethe output power is shown as a function of the output coupler for twofiber lengths, 20 m and 15 m. The clad and core configuration isidentical to the embodiment of FIG. 8, and 459 nm is the first Ramanorder for these fibers when pumped with the 450 nm center wavelength ofthe laser diodes. This wavelength can be stabilized using a Volume BraggGrating with a nominal effect on the output power if wide bandtemperature operation is desired

An embodiment of a blue laser diode pump, producing a 450 nm beam, wasmeasured using a 500 mm focal length lens to determine the beam causticand consequently the fiber diameter that the laser array can be launchedinto. FIG. 10 shows the beam waist as a function of the output powerwhich does not vary substantially with the output power of the device.This figure shows that the slow axis has a 1/e² waist of 200 μm whichtranslates to a 30 μm beam waist when using an 80 mm focal length lens.FIG. 10 also has the fast axis graphed. This implies that for thisembodiment a coupling efficiency in excess of 90% can be achieved into a62.5 μm diameter fiber. The pump power and brightness can be doubled byusing both polarization states prior to launching into the 62.5 μmdiameter fiber. Thus in this embodiment there will be about greater than60 Watts output with 200 Watts input into the Raman oscillator laserfiber.

The high brightness blue laser diodes used in the embodiments of FIGS.7-10 provide sufficient fluence to create enough gain in the single modecore to allow Raman oscillation and thus provide a Raman generated laserbeam. Thus, these present embodiments overcome one of the key issuespreventing the development of a visible Raman laser. That issue beingthe high losses in an optical fiber at visible wavelengths. This isbelieved to be one of, if not the key reason, why prior to the presentinventions a visible Raman oscillator laser was overlooked by the artand has not been demonstrated or proposed by others.

Embodiments of the Raman oscillator of the present inventions can bemade from many different types of materials. Preferably, for fibers,they are silica based and would include silica based fibers that havebeen doped with GeO₂ or P₂O₅, which characteristics are shown in TableIll. Other heavy metals may also be used as dopants for various types ofoscillators, where the operating wavelength is close to the band edgefor absorption which causes an anomalous Raman gain that can besubstantially higher than conventional sources. An example of this for500 nm light would be Tellurite doped glass where the Raman gain isalmost a factor of 40× greater than fused silica. Other dopants may beused with similar results at the target wavelength of 450 nm.

In a preferred embodiment there is a high NA outer cladding, for adouble clad fiber with the cladding being relatively low loss at thepump wavelength and the core being >3 μm, >10 μm and including in someembodiments >20 μm. The Clad/Core ratio preferably is maintained belowthe threshold for self-oscillation of the second Stokes order. The firstStokes gain is determined by the intensity of the light in the cladwhich is coupled into the core while the gain of the second order Stokesis determined by the oscillation of the first order Stokes in the core.As mentioned previously, this becomes a limiting factor and is dependenton the losses in the fiber, the oscillating power in the first orderStokes, the length of the fiber, and thus total gain, and the feedbackif any at the second order Stokes signal. This process ultimately limitsthe amount of brightness enhancement that can be achieved with thismethod, which can be address, for example, by the scalability shown inFIG. 18, where the Raman source requires a wavelength beam combinationmethod to achieve high brightness and high power.

Raman amplification has a very wide bandwidth enabling modulation rateswell into the GHz regime. This rapid modulation is feasible with theblue Raman laser source because of the short lifetimes associated withthe inversion process. The rapid modulation capability can providesignificant benefits in additive manufacturing applications, where forexample the part has a high spatial frequency, or sharp details thatneed to be reproduced. Ideally, the faster the laser can be turned onand off, the faster the part can be printed. For example in anembodiment for a given scanning speed, the spatial frequencies of thepart become the limitation on the printing rate because a laser whichcan only be modulated at a few kHz requires the scanners to move at aslow speed to replicate the fine details and spatial frequency of thepart, however, a laser which can be modulated in the 10's of GHz regime,allows the part to be rapidly scanned and as a consequence, rapidlyprinted.

Table IV shows a comparison of the fiber laser build rate to the buildrate for an equivalent power level blue laser. This table shows that fora given spot size, the blue laser can achieve a larger build volume anddepending on the material being compared speed increases between 1.2×(Titanium) to >80× (gold) based on the enhanced absorption of the laserwavelength.

TABLE IV Improvement Fiber Laser Blue Laser in Performance (1070 nm)(459 nm) build speed Power 1000 W 1000 W Resolution (Spot 70 um 70 umsize diam) Build Volume 24.8″ × 15.7″ × 19.7″ 48″ × 32″ × 40″ PrintSpeed cc/hr cc/hr Comparison Al 5 14  262% Cu 4 66 1630% Au 0.8 67 8275%Ni 29 50  173% Ag 1 17 1690% SS304 30 44  144% Ti 65 82  126%

Turning to FIG. 13A there is shown the transitions that take placethrough three Raman orders, stokes, to provide a 478 nm functional laserbeam from a 450 nm pump source.

Examples of Raman fiber lasers, having different materials, and theirrespective wavelength outputs for n-order stokes shifts, when pumpedwith a 450 nm laser, are shown in FIGS. 13B & 13C. These fibers all havea 20 μm diameter core, and a 50 μm clad thickness.

Turning to FIG. 14A there is shown the transitions that take placethrough three Raman orders, anti-stokes, to provide a 425 nm functionallaser beam from a 450 nm pump source.

Examples of Raman fiber lasers, having different materials, and theirrespective wavelength outputs for n-order stokes shifts, when pumpedwith a 450 nm laser, are shown in FIGS. 14B & 14C. These fibers all havea 20 μm diameter core, and a 50 μm clad thickness.

Turning to FIG. 15 there is shown the Raman spectra in a phosphosilicatedoped fiber. P₂O₅ concentrations of in the fiber are:18 mol %, line 1; 7mol %, line 2; and for fused silica fiber with no P₂O₅ (e.g., 0 nik %),line 3. Thus, laser emission can be achieved over a wide range offrequencies from a few cm⁻¹ to 1330 cm⁻¹.

The following examples are provided to illustrate various embodiments ofLAM systems, LAM methods, and Raman oscillator lasers of the presentinventions. These examples are for illustrative purposes and should notbe viewed as, and do not otherwise limit the scope of the presentinventions.

EXAMPLE 1

A Raman Laser Module (RLM) has a forward pump Raman Standard LaserModule as the pump laser to a Raman laser oscillator fiber to provide a200 W, M² of about 1, 460 nm laser beam that can be modulated up to 2MHz for various and predetermined manufacturing applications. The pumpStandard Laser Module (SLM) provides a 200 W, 10 mm-mrad, ˜450 nm laserbeam to be used as a forward pump for the laser oscillator fiber. Theoscillator fiber has a 60-100 μm clad, a 10-50 μm core and provides a200 W Output, <0.3 mm-mrad, ˜460 nm laser beam.

EXAMPLE 2

Five RLMs of Example 1 are in the additive manufacturing system of FIG.5. Their beams are combined to form a single 1 kW functional laser beam.The embodiment of this example can be used to print, e.g., build ormake, metal based articles.

EXAMPLE 3

Five RLMs of Example 1 are in the additive manufacturing system of FIG.6. Their beams are combined to form a single 1 kW functional laser beam.The embodiment of this example can be used to print, e.g., build ormake, metal based articles.

EXAMPLE 4

Seven RLMs of Example 1 are in the 3-D printer of FIG. 5. Their beamsare combined to form a single 1.4 kW functional laser beam. Theembodiment of this example can be used to print, e.g., build or make,metal based articles.

EXAMPLE 5

Ten RLMs of Example 1 are in the additive manufacturing system of FIG.6. Their beams are combined to form a single 2 kW functional laser beam.The embodiment of this example can be used to print, e.g., build ormake, metal based articles.

EXAMPLE 6

A Raman Laser Module (RLM) has a backward pump Raman Standard LaserModule as the pump laser to a Raman laser oscillator fiber to provide a200 W, M² of about 460 nm laser beam that can be modulated up to 2 MHzfor various and predetermined manufacturing applications. The pumpStandard Laser Module (SLM) provides a 200 W, 10 mm-mrad, ˜450 nm laserbeam to be used as a backward pump for the laser oscillator fiber. Theoscillator fiber has a 60-100 μm clad, a 10-50 μm core and provides a200 W Output, <0.3 mm-mrad, ˜460 nm laser beam.

EXAMPLE 7

Five RLMs of Example 6 are in the additive manufacturing system of FIG.5. Their beams are combined to form a single 1 kW functional laser beam.The embodiment of this example can be used to print, e.g., build ormake, metal based articles.

EXAMPLE 8

Eight RLMs of Example 6 are in the additive manufacturing system of FIG.6. Their beams are combined to form a single 1.6 kW functional laserbeam. The embodiment of this example can be used to print, e.g., buildor make, metal based articles.

EXAMPLE 9

One RLM of Example 6 is in the additive manufacturing system of FIG. 5.The LRM provides a single 0.2 kW functional laser beam. The embodimentof this example can be used to print, e.g., build or make, metal basedarticles.

EXAMPLE 10

A high power Raman Laser pumped by high brightness blue laser diodeswith >1 Watt output power at any n-Raman orders from the originatingpump wavelength.

EXAMPLE 11

The use of the laser of Example 10 for material processing applicationssuch as welding, cutting, heat treating, brazing and surfacemodification.

EXAMPLE 12

A high power blue laser diode system (405 nm-475 nm) that canlaunch >100 Watts into a >50 μm fiber.

EXAMPLE 13

A high power blue laser diode system with >5 mm-mrad beam parameterproduct to pump a Raman fiber laser.

EXAMPLE 14

A high power blue laser diode system with >10 mm-mrad beam parameterproduct to pump a Raman fiber laser.

EXAMPLE 15

A high power blue laser diode system pumping an n-Raman order fiberlaser to achieve any visible wavelength.

EXAMPLE 16

A high power blue laser diode system pumping a Raman fiber laser withoutputs on all n-orders, where n>0.

EXAMPLE 17

A high power Raman laser system with 2>M²>1 beam quality.

EXAMPLE 18

A high power Raman laser system with >1 Watts operating at 410-500 nmthat can be used for processing materials.

EXAMPLE 19

A high power blue Raman laser system with >1000 Watts for cutting,welding, brazing, polishing and marking materials.

EXAMPLE 20

A high power blue Raman laser system >10 Watts with a high power diodepump system that is modular in design.

EXAMPLE 21

A high power blue Raman laser system >10 Watts that has an air cooledblue diode laser pump.

EXAMPLE 22

A high power blue diode laser system that is spectrally beam combined toproduce a <10 nm composite beam that can be used to pump a high powerRaman laser system.

EXAMPLE 23

A high power blue Raman laser system >10 Watts that is spectrally beamcombined to produce a composite beam with a low M² value, e.g., lessthan 2.5, less than 2.0, less than 1.8, and less 1.5, and less than 1.2.

EXAMPLE 24

A high power blue Raman laser and amplifier system >10 Watts that iscoherently combined to produce a very high power diffraction limitedbeam.

EXAMPLE 25

A high power blue diode laser system of Example 23 that uses a prism tospectrally beam combine.

EXAMPLE 26

A high power blue diode laser Raman laser pump of Example 23 that uses adiffractive element to spectrally beam combine.

EXAMPLE 27

A high power blue diode laser Raman laser pump of Example 23 that uses avolume Bragg grating to spectrally beam combine.

EXAMPLE 28

A high power blue Raman laser >10 Watts for combination with a digitalmirror device for projecting a color image including 3-D capability.

EXAMPLE 29

A high power blue Raman laser with >10 Watts for entertainment purposes.

EXAMPLE 30

A high power blue Raman laser >10 Watts for pumping a phosphor forproducing a white light source that can be used in projection systems,headlights, or illumination systems.

EXAMPLE 31

An array of high power blue laser diode modules locked to a narrowwavelength band by a volume bragg grating for pumping a Raman fiberlaser system.

EXAMPLE 32

An array of high power blue laser diode modules locked to a narrowwavelength band by a fiber Bragg grating for pumping a Raman fiber lasersystem.

EXAMPLE 33

An array of high power blue laser diode modules locked to a narrowwavelength band by a transmissive grating for pumping a Raman fiberlaser.

EXAMPLE 34

An array of high power blue laser diode modules locked to a range ofwavelengths by a transmissive grating for pumping an n-order Ramanlaser.

EXAMPLE 35

An air cooled or water cooled heat exchanger attached to the backplaneto dissipate the heat from the laser diode modules and a Raman Fiberlaser.

EXAMPLE 36

A laser diode module with integral drive electronics to control thecurrent and enable the rapid pulsing of the laser diode for pumping aRaman laser.

EXAMPLE 37

A high power Raman laser based on a convertor material such as Diamondwhere the Raman laser is pumped by a visible laser diode array that ismode matched to the Raman laser mode.

EXAMPLE 38

The use of the laser in Example 37 for material processing such aswelding, cutting, brazing, heat treating, and surface modification.

EXAMPLE 39

The building speed of an embodiment of a UV laser (350 nm) of thepresent inventions is compared against the build speed of a prior art IRfiber laser (1070 nm). From the above Table IV, it can be seen thatsignificantly greater build speeds are obtainable with embodiments ofthe present inventions.

EXAMPLE 40

The embodiments of Examples 1-8 can be combined with, or otherwiseincorporated into a milling machine, such as a CNC machine, or laser,sonic, water jet, mechanical or other type of milling, machining orcutting apparatus. In this manner there is a Raman additive-subtractivemanufacturing apparatus and process. In an embodiment the functionalRaman laser beam can be used to build an article, which is then furthermachined, i.e., material is removed. The Raman laser beam can be used toadd lost material to a worn article that is further machined. Othervariations and combinations of adding, removing and adding material toreach a final product, part or article are contemplated. Thus, there isprovided in one embodiment the removal of Raman laser beam addedmaterial. In a laser machining additive-subtractive apparatus andprocess, the laser used for removal (e.g., subtractive manufacturing,the cutting laser beam, the machining laser beam), can be a Ramangenerated beam, the LAM functional beam, or a separate beam having adifferent wavelength (e.g., IR, such as a wavelength >1,000 nm), thecutting laser beam and the functional laser beam (LAM beam) can followessentially the same beam delivery paths, can follow substantiallydistinct beam delivery paths, and can share, some, all or none of thebeam shaping and delivery optics, and combinations and variations ofthese.

EXAMPLE 41

The embodiments of Examples 1-8 have a table that is a longitudinallymoving surface, or support structure, such as a belt, conveyor, orarticulated and overlapping leafs, which allow for the making ofcontinuous ribbon, rods, fiber, rope, wire, tubular, band or otherelongate structures.

EXAMPLE 42

The embodiments of Examples 1 and 6 are used in the additivemanufacturing system of FIG. 17. The system 1700 has a hopper 1701 forholding the starting material, an adjustable metering plate 1702 fordelivering the starting material, a working station 1703, a transportchamber 1704, a metering plate actuator pin 1705, a shuttle 1711, a rackand pinion shuttle drive 1706, a shuttle stepper motor 1707, a waste bin1708, an elevator stepper motor 1709, and an elevator 1710.

EXAMPLE 43

A LAM system is a galvo-scanned powder bed processes and system. Thelaser delivery apparatus has a collimator/beam expander for the laserbeam and an X-Y galvo scanning system, and an F-Theta lens. Thecollimator/beam expander can be fixed ratio or variable depending on thebuild process, if a larger spot size is needed, then the beam expanderratio is decreased. Similarly if a smaller spot size on the part isneeded, then the beam expander ratio is increased to create a largerdiameter launch beam. The powder is placed with a starting materialdelivery system on the worktable and leveled with a leveling mechanism.In this embodiment, the motion of the table is only needed in the zaxis. A variable focus lens in the laser beam path could also beutilized to accomplish z axis movement.

EXAMPLE 44

A high power blue laser diode system with >10 mm-mrad beam parameterproduct that can be used to weld, cut, braze, polish and mark materialssuch as metals, plastics and non-metal materials.

EXAMPLE 45

RLMs are coherently combined using either a master oscillator poweramplifier configuration, or a Fourier transform external cavity.Examples of systems for coherent beam combining are disclosed and taughtin U.S. Pat. No. 5,832,006, the entire disclosure of which isincorporated herein by reference.

It is noted that there is no requirement to provide or address thetheory underlying the novel and groundbreaking processes, materials,performance or other beneficial features and properties that are thesubject of, or associated with, embodiments of the present inventions.Nevertheless, various theories are provided in this specification tofurther advance the art in this area. The theories put forth in thisspecification, and unless expressly stated otherwise, in no way limit,restrict or narrow the scope of protection to be afforded the claimedinventions. These theories many not be required or practiced to utilizethe present inventions. It is further understood that the presentinventions may lead to new, and heretofore unknown theories to explainthe function-features of embodiments of the methods, articles,materials, devices and system of the present inventions; and such laterdeveloped theories shall not limit the scope of protection afforded thepresent inventions.

The various embodiments of systems, equipment, techniques, methods,activities and operations set forth in this specification may be usedfor various other activities and in other fields in addition to thoseset forth herein. Additionally, these embodiments, for example, may beused with: other equipment or activities that may be developed in thefuture; and with existing equipment or activities which may be modified,in-part, based on the teachings of this specification. Further, thevarious embodiments set forth in this specification may be used witheach other in different and various combinations. Thus, for example, theconfigurations provided in the various embodiments of this specificationmay be used with each other; and the scope of protection afforded thepresent inventions should not be limited to a particular embodiment,configuration or arrangement that is set forth in a particularembodiment, example, or in an embodiment in a particular Figure.

The invention may be embodied in other forms than those specificallydisclosed herein without departing from its spirit or essentialcharacteristics. The described embodiments are to be considered in allrespects only as illustrative and not restrictive.

What is claimed:
 1. A laser additive manufacturing (LAM) apparatus comprising: a. a laser for providing a functional laser beam along a beam path, the functional laser beam having a wavelength less than about 750 nm; b. a build table; c. a starting material, and a starting material delivery apparatus, wherein the starting material can be delivered to a target area adjacent the build table; d. a laser beam delivery apparatus, comprising a beam shaping optic to form a laser beam spot; e. a motor and positioning apparatus, mechanically connected to the build table, the laser beam delivery apparatus, or both; whereby the motor and positioning apparatus are capable of providing relative movement between the laser beam delivery apparatus and the build table; f. a control system, the control system comprising a processor, a memory device and a LAM plan wherein the LAM plan is in the memory device, wherein the control system is capable of implementing the LAM plan through the predetermined placement of the functional laser beam and the starting material; and, g. wherein the laser comprises a pump laser diode and a Raman oscillator that are configured to provide an n-order Raman oscillation, where n is an integer.
 2. The apparatus of claim 1, wherein n is selected from the group consisting of 2, 3, 4, 5, and
 6. 3. The apparatus of claim 2, wherein the build material is selected from the group consisting of Magnesium, Aluminum, Gallium, Tin, Lead, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Zirconium, Molybdenum, Rhodium, Palladium, Silver, Cadmium, Tungsten, Gold, Mercury, metals, alloys of metals, and mixtures of metals.
 4. The apparatus of claim 3, wherein the starting material is a powder having a particle size from about 0.05 μm to about 2.5 μm.
 5. The apparatus of claim 1, wherein the n-order oscillation is stokes.
 6. The apparatus of claim 1, wherein the n-order oscillation is anti-stokes.
 7. The apparatus of claim 1, wherein the build material is selected from the group consisting of Magnesium, Aluminum, Gallium, Tin, Lead, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Zirconium, Molybdenum, Rhodium, Palladium, Silver, Cadmium, Tungsten, Gold, Mercury, metals, alloys of metals, and mixtures of metals.
 8. The apparatus of claim 7, wherein the starting material is a powder having a particle size less than about 25 μm.
 9. The apparatus of claim 7, wherein the starting material is a powder having a particle size less than about 15 μm.
 10. The apparatus of claim 7, wherein the starting material is a powder having a particle size less than about 0.5 μm.
 11. The apparatus of claim 1, wherein the starting material is a powder.
 12. The apparatus of claim 1, wherein the starting material is a powder having a particle size less than about 1 μm.
 13. The apparatus of claim 1, wherein the starting material is a powder having a particle size from about 0.05 μm to about 2.5 μm.
 14. The apparatus of claim 1, wherein the starting material is a powder having a particle size from about 40 μm and smaller.
 15. A Raman laser modules (RLM) for use in laser additive manufacturing, the RLM comprising: a pump laser beam source and a Raman oscillator for providing a functional laser beam; the functional laser beam having a wavelength less than about 700 nm, a M² of less than 2, and a power of greater than 500 W.
 16. The apparatus of claim 15, wherein the pump laser source comprises a plurality of laser diodes to produce a pump laser beam having a beam parameter product from about 9 to about 14 mm-mrad.
 17. The apparatus of claim 15, wherein the Raman oscillator comprises a crystal oscillator comprising material selected from the group consisting of Diamond, KGW, YVO₄, and Ba(NO₃)₂.
 18. The apparatus of claim 15, wherein the Raman oscillator comprises a fiber oscillator comprising a material selected from the group consisting of Silica, GeO₂ doped silica, Phosphorus doped silica.
 19. The apparatus of claim 18, wherein the oscillator fiber has a length and the length is about 20 m or less.
 20. The apparatus of claim 18, wherein the functional laser beam has a wavelength of from about 405 nm to about 470 nm.
 21. The apparatus of claim 15, wherein the pump laser source comprises a diode laser.
 22. The apparatus of claim 15, wherein the pump laser source comprises a plurality of laser diodes to produce a pump laser beam having a beam parameter product of less than about 10 mm-mrad.
 23. The apparatus of claim 22, wherein the oscillator fiber has a length and the length is about 25 m or less.
 24. The apparatus of claim 15, wherein the pump laser source comprises an array of at least 20 blue laser diodes.
 25. The apparatus of claim 24, wherein the array provides a pump laser beam having a wavelength in the range of about 405 nm to about 460 nm.
 26. The apparatus of claim 25, wherein the oscillator fiber has a length and the length is about 20 m or less.
 27. The apparatus of claim 25, wherein the functional laser beam has a wavelength of from about 405 nm to about 470 nm.
 28. The apparatus of claim 15, wherein the oscillator fiber has a length and the length is about 30 m or less.
 29. The apparatus of claim 15, wherein the functional laser beam has a wavelength of from about 405 nm to about 470 nm.
 30. The apparatus of claim 15, wherein the pump laser source comprises a blue laser diode system, the system providing a pump laser beam having a wavelength of about 405 nm-475 nm, a power of greater than 100 W; and wherein the Raman oscillator fiber has a core diameter of about 10 μm-50 μm and is a graded index fiber.
 31. The system of claim 15, wherein the pump laser source is cooled, and the cooling is selected from the group consisting of air cooled, liquid cooled and water cooled.
 32. The system of claim 15, wherein the pump laser source comprises a spectral beam combiner.
 33. A system comprising a plurality of the RLMs of claim 15, wherein laser beams from the RLMs are coherently combined to form a single functional laser beam.
 34. The system of claim 15, wherein the pump laser source comprises a laser diode and integral drive electronics to control the current and enable the rapid pulsing of the pump laser source diode to provide a pulsed pump laser beam.
 35. The system of claim 34, wherein the pulse rate to from about 0.1 MHz to about 10 MHz.
 36. The apparatus of claim 15, wherein the Raman oscillator comprises a high pressure gas.
 37. The apparatus of claim 15, wherein the pump laser source comprises a plurality of laser diodes to produce a pump laser beam having a beam parameter product of less than about 14 mm-mrad.
 38. A 3-D printing apparatus comprising a starting material delivery apparatus, wherein a starting material can be delivered to a target area adjacent a predetermined build area; a beam shaping optic to provide a functional laser beam spot having a cross section of less than about 100 microns at the build area; and a Raman laser module (RLM).
 39. The 3-D printing apparatus of claim 38, wherein the RLM comprises: a pump laser beam source and a Raman oscillator; the functional laser beam having a wavelength less than about 700 nm, a M² of less than 2, and a power of greater than 500 W.
 40. The 3-D printing apparatus of claim 39, wherein the functional laser beam has a wavelength of from about 405 nm to about 470 nm.
 41. The 3-D printing apparatus of claim 39, wherein the functional laser beam has a wavelength in the 500s nm range.
 42. The 3-D printing apparatus of claim 39, wherein the Raman oscillator comprises a fiber oscillator comprising a material selected from the group consisting of Silica, GeO₂ doped silica, Phosphorus doped silica.
 43. The 3-D printing apparatus of claim 39, wherein the pump laser source comprises an array of at least 20 blue laser diodes.
 44. The 3-D printing apparatus of claim 43, wherein the array provides a pump laser beam having a wavelength in the range of about 405 nm to about 460 nm. 